How to implement ng-class to md-chip in angular-material

Question

Here is my problem - i can't implement ng-class='{activeTag: $chip.active}' to <md-chip></md-chip>. I've been tried to add this directive to <md-chips></md-chips> but it doesn't works(because of $chip not in current scope). I also can add this ng-class to md-chip-template but visually it's not what i want, i need backlight for everything in tag. Btw, <md-chip></md-chip> dynamically created in md-chips directive. Maybe someone faced with this problem or just know the solution. Thanks.

Here is my controller

controller('ChipsController', function($scope) {
    $scope.tags = [
      {
        id: 1,
        name: 'Pop',
        active: false
      },
      {
        id: 2,
        name: 'Rock',
        active: true
      },
      {
        id: 3,
        name: 'Reggie',
        active: false
      }
  ];

});

My view

<md-chips class="custom-chips selected" ng-model="tags" readonly="true">
<md-chip-template ng-class="{'activeTag': $chip.active}" style="cursor: pointer;">
  <a ui-sref="">
    <strong>{{$chip.id}}</strong>
    <em>({{$chip.name}})</em>
  </a>
</md-chip-template>

My css

.activeTag {
  background: rgba(85, 107, 47, 0.66) !important;
  color: white !important; 
}

Here is the plunker

Answer 1

I may prefer to use custom directive, which add special class to your chip

.directive('myChip', function(){
    return {
        restrict: 'EA',
        link: function(scope, elem, attrs) {
            var myChip = elem.parent().parent();
            myChip.addClass('_active');

            scope.$watch(function(){
                return scope.$chip.active
            }, function(newVal){
                if (newVal) {
                  myChip.addClass('_active');
                } else {
                  myChip.removeClass('_active');
                }
            })

        }
    }
})

template

<md-chip-template ng-class="{'activeTag': $chip.active}" style="cursor: pointer;" my-chip>

styles

.md-chip._active {
  background: rgba(85, 107, 47, 0.66) !important;
  color: white !important;
}

http://plnkr.co/edit/vv2SvH1gNj3OIh1oaqvV?p=preview